It is known that the usage purpose of the outer enveloping shell in the Christmas lamp mainly is to further adjust the light sources of lamps such that different light sources can create different lighting effects. For example, different colored outer enveloping shells can be used to change then create lights with different colors, or the shell surface of an outer enveloping shell is made the processed with different veins to create different shining lighting. By the extension of this effect, it is gradually become popular currently in the market that a single outer enveloping shell is made and processed with two or more than two kinds of colors or veins to let the single Christmas lamp itself create more than two kinds of light sources' effects. And the processing method in the outer enveloping shell is to paint the shell surface with different colors or carve the shell surface with different vein. However, the case of color fading is occurred easily in the outer enveloping shell processed by the said method, and it takes time and work if processed by carving the shell surface then increase the manufacturing cost. Thus, these two processing methods both are not ideal enough and need to be improved.